MOS devices can serve as resistors when used in the triode region of operation. Even though, they have certain advantages such as trimmability, small area, and potential to achieve very large values, MOS resistors are also non-linear due to MOS I-V characteristics. Non-linear behavior can cause undesired effects such as intermodulation between signals at terminals of the MOS resistor. One adverse outcome of the intermodulation is undesired DC offset across the MOS resistor, when it is subject to AC signals.
There is thus a need for a method and apparatus for eliminating DC producing intermodulation, hence, preventing complications such as loss of dynamic range in the circuit utilizing the MOS resistor.